Brief Summary

Introduction

The members of the Promachoteuthidae are mostly small, weakly muscled squids that seem to occur exclusively in the great depths of the bathypelagic zone of the world's oceans. Species of Promachoteuthis are known from only 12 specimens (two have not been described in the literature - Voss, 1992) among five, mostly geographically restricted, species. Although the data are few, the apparent high diversity and restricted distributions are unexpected for cephalopods inhabiting the bathypelagic region of the world's oceans. Maximum size recorded is a 184 mm ML mature male (Voss, 1992) but this specimen has not been described. A distinctive feature is the reduction in the size of the eyes which is exteme in Promachoteuthis sp. B. This species has the smallest eyes (relative to the squid size) of all squids and their eyes are buried in gelatinous tissues of the head but retain contact with sea water via slender canals. Little is known of the biology of these rare squids.